What Is Dark Matter? Colliding Galaxy Clusters May Help Find Answer

Dark matter is a hypothetical kind of matter that cannot be seen with telescopes but accounts for most of the matter in the universe.  Dark matter is estimated to constitute 84.5% of the total matter in the universe. It has not been detected directly, making it one of the greatest mysteries in modern astrophysics.



Hubble Image of Galactic Collision 

A study of 72 large cluster collisions shows how dark matter in galaxy clusters behaves when they collide.

Image Showing How two Galaxies Collides

Astronomers have used data from NASA’s Hubble Space Telescope and the Chandra X-ray Observatory to find that dark matter interacts with itself less than previously thought. In an effort to learn more about dark matter, astronomers observed how galaxy clusters collide with each other -- an event that could hold clues about the mysterious invisible matter that makes up most of the mass of the universe.

As part of a new study, published in the journal Science on Thursday, researchers used the Hubble telescope to map the distribution of stars and dark matter after a collision. They also used the Chandra observatory to detect the X-ray emission from colliding gas clouds.

“Dark matter is an enigma we have long sought to unravel,” John Grunsfeld, assistant administrator of NASA’s Science Mission Directorate in Washington, said in a statement. “With the combined capabilities of these great observatories, both in extended mission, we are ever closer to understanding this cosmic phenomenon.”



Here are images of six different galaxy clusters taken with NASA's Hubble Space Telescope (blue) and Chandra X-ray Observatory (pink) in a study of how dark matter in clusters of galaxies behaves when the clusters collide. A total of 72 large cluster collisions were studied.  NASA and ESA

According to scientists, galaxy clusters are made of three main components -- galaxies, gas clouds and dark matter. During collisions, the gas clouds bump into each other and gradually slow down. Galaxies, on the other hand, are much less affected by this process, and because of the huge gaps between the stars within them, galaxies do not slow each other down.

“We know how gas and stars react to these cosmic crashes and where they emerge from the wreckage,” David Harvey of the École Polytechnique Fédérale de Lausanne in Switzerland, and the study’s lead author, said in the statement. “Comparing how dark matter behaves can help us to narrow down what it actually is.”

The researchers studied 72 large galaxy cluster collisions and found that, like galaxies, the dark matter continued straight through the collisions without slowing down much, meaning that dark matter do not interact with visible particles.

“There are still several viable candidates for dark matter, so the game is not over. But we are getting nearer to an answer,” Harvey said.

Source : IBT times

Hubble Captures 'Happy Face' of Universe

Hubble Takes a Amazing Picture which seems like Happy Face in the Space.

Of course, this is neither a miracle nor a edited picture.

The reason behind this 'Happy face' is very Complex Phenomena called Gravitational Lensing. The Eyes of the face are two Galaxies but Face's smile is due to gravity. Gravitational lensing is one of the most fascinating thing in Physics and astronomy.

This picture shows the true power of gravity. The gravity of these massive galaxies are so intense that they even distort the space-time create this amazing lens effect. The light itself distorted and gives the magnified view of galaxies.

Some astronomer believes that it is because of Dark matter, an unknown matter which is yet to be discover. These images are the strong evidence of dark matter but further research and experiments are needed to entirely prove their existence.

Hubble takes many images which shows gravitational lensing

Hubble spots massive 'eye in the sky'

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It might look like a giant eye in the sky, or something from a science fiction fiction film, but in fact this incredible image reveals just how violent planet formation is.

Captured by the Hubble Space Telescope, it shows the huge dusty debris discs around stars.

Created by collisions between leftover objects from planet formation, were imaged around stars as young as 10 million years old and as mature as more than 1 billion years old in Nasa's images.

The researchers discovered that no two "disks" of material surrounding stars look the same.

“We find that the systems are not simply flat with uniform surfaces,” Schneider said.

Source: dailymail

Galaxies probably settled 2 billion years earlier than previously believed

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Scientists have dug deeper and discovered that galaxies actually settled in to their current forms some 2 billion years earlier than previously thought.

A group of researchers used the collective efforts of the hundreds of thousands of people that volunteered for the galaxy Zoo project to shed some light on the way that galaxies form and develop.

Dr. Brooke Simmons of the University of Oxford and her collaborators set Zoo volunteers the task of classifying the shapes of tens of thousands of galaxies observed by the Hubble Space Telescope. These objects are typically very distant, so they appeared more than 10 billion years ago, when the universe was about 3 billion years old, less than a quarter of its present age.

The newly classified galaxies were striking in that they look a lot like those in today's universe, with disks, bars and spiral arms. But theorists predict that they should have taken another 2 billion years to begin to form, so things seem to have been settling down a lot earlier than expected.

Brooke commented that they had predictions from galaxy simulations that they shouldn't find any of the barred features that we see in nearby, evolved galaxies, because very young galaxies might be too agitated for them to form. But with the public help they got in searching through many thousands of images of distant galaxies, they have discovered that some galaxies settle very early on in the universe.

The paper is published in Monthly Notices of the Royal Astronomical Society.

Source : Zee News

Jupiter's ‘one-eyed giant Cyclops’ captured by Hubble

A stunning event captured by NASA’s Hubble Telescope shows a big black eye staring back from Jupiter's Great Red Spot storm. In reality, it is shadow play on a planetary scale.

The image was captured by NASA’s Hubble Space Telescope as it tracked changes in Jupiter’s immense Great Red Spot storm – a storm that has been raging for over 300 years. The black eye is caused by the shadow of the Jovian moon, Ganymede, sweeping across the center of the storm.

“For a moment, Jupiter stared back at Hubble like a one-eyed giant Cyclops,” a NASA spokesman told the Daily Express.

The Great Red Spot, the largest known vortex in the Solar System at 10,000 miles wide, is a persistent anti-cyclonic storm just south of Jupiter's equator. It has been raging for between 300 and 400 years, blowing winds at 345 miles an hour – speeds that are beyond comparison with even an Earthly Category 5 hurricane, which can only maximize up to 200 miles.

Astronomers are only beginning to fully understand the complexity of Jupiter, a gas giant which has a mass 317 times bigger than Earth. The planet has 62 moons – including four large ones called the Galilean moons, first discovered by Galileo Galilei in 1610. Ganymede is the largest of these moons.

Hubble captures stunning image of a comet's brush past Mars

NASA has just released this image of comet Siding Spring's close brush past Mars, and it is thrilling.

The image you see above -- a fuzzy white comet hovering above a glowing rust-colored planet -- is actually a composite of several images taken by the Hubble Space Telescope on Saturday and Sunday.

NASA's Hi Res camera aboard a Mars orbiter captured the first images of the nucleus of a comet
There are a few reasons that Hubble could not take a picture like this in a single shot. For one, Mars is 10,000 times brighter than its cometary visitor, making it impossible to see details of Siding Spring and Mars in one exposure.

Also, the two objects were racing past each other during their near-rendezvous on Sunday. At least one of the objects would have been blurry if Hubble tried to take an image of them simultaneously.

The starfield that the two bodies are set against was provided by the Palomar Digital Sky Survey.

Despite being a bit of a cut and paste job, NASA officials say the image accurately illustrates the distance between Siding Spring and Mars at the time of the comet's closest approach.

It also accurately represents the relative sizes of the two bodies.